chore: add ROOT_DIR environment variable, refactor

internal/common/paths.go

@@ -0,0 +1,31 @@
+package common
+
+import (
+	"path/filepath"
+)
+
+// file, folder structure
+
+var (
+	ConfigDir             = filepath.Join(RootDir, "config")
+	ConfigFileName        = "config.yml"
+	ConfigExampleFileName = "config.example.yml"
+	ConfigPath            = filepath.Join(ConfigDir, ConfigFileName)
+
+	MiddlewareComposeDir = filepath.Join(ConfigDir, "middlewares")
+	ErrorPagesDir        = filepath.Join(RootDir, "error_pages")
+	CertsDir             = filepath.Join(RootDir, "certs")
+
+	DataDir        = filepath.Join(RootDir, "data")
+	MetricsDataDir = filepath.Join(DataDir, "metrics")
+
+	HomepageJSONConfigPath = filepath.Join(DataDir, "homepage.json")
+	IconListCachePath      = filepath.Join(DataDir, "icon_list_cache.json")
+	IconCachePath          = filepath.Join(DataDir, "icon_cache.json")
+)
+
+var RequiredDirectories = []string{
+	ConfigDir,
+	ErrorPagesDir,
+	MiddlewareComposeDir,
+}